One type of modern refrigerant compressor is a scroll compressor. In a scroll compressor, a pair of scroll members each include a base and a generally spiral wrap extending from the base. The wraps interfit to define compression chambers. One of the two scroll members is caused to orbit relative to the other. As the two orbit relative to each other, there is a force at a rubbing interface between these two scroll members. One of the types of the interfaces between the scroll compression members is the interface between the base and wrap tips of the opposing scroll members. If there is not enough lubrication provided in the interface between these two members, it can lead to scroll element damage. Thus, during operation of a scroll compressor it is important to have a film of lubricant in the interface between the two scroll members. This application relates to a unique way of maintaining a small amount of lubricant in an orbiting and non-orbiting scroll elements interface to provide enhanced lubrication for a compressor during a starved lubrication on start-up or during continuous operation.
Sealed compressors are a part of refrigerant compression systems. A refrigerant system includes a number of components. Refrigerant flow lines connect the system components, and the refrigerant flows between the compressor and other components within the system such as the condenser, the evaporator and the expansion device, etc. At the same time, lubricant carried by the refrigerant also flows between the system components.
Often after shutdown of the system, the residual lubricant that remains inside the scroll compressor elements, such as orbiting and non-orbiting scroll, can drain from these elements. If sufficient amount of lubricant is missing from the orbiting and non-orbiting scroll interface then compressor damage can result when the scroll elements begin to rub against each during operation. This situation becomes particularly acute for a compressor that was shutdown for long periods, as lack of lubricant between the engaged scroll members can lead to the damage of these members upon compressor start up, before the sufficient amount of lubricant has been delivered to the scroll elements after the compressor started its operation. Other events occurring during operation of the refrigerant cycle may also cause momentary loss of oil supply at the compressor. This event can include compressor flooding, when the liquid refrigerant entering the scroll compressor elements can wash away the lubricant inside the scroll compressor pumping elements. Another event includes a situation when there is an insufficient amount of oil circulating through the scroll compressor pumping elements, in other words the scroll compressor elements are starved of sufficient amount of oil in the interface of the scroll compressor pumping elements. During the starved lubricant condition there is little or no lubricant in the interface, thus damage can quickly occur.
U.S. Pat. No. 6,354,822 discloses a method of preventing a starved lubricant condition between a slider block and an eccentric pin in a scroll compressor. However, there has been no similar provision to provide oil to the interface between the two scroll elements.